JP6907927B2 - Adhesive compositions, laminates, packaging materials for power storage devices, containers for power storage devices and power storage devices - Google Patents

Description

The present invention relates to an adhesive composition. The present invention also relates to a laminated body and a packaging material for a power storage device in which a metal foil and a heat-sealed resin film are laminated using the adhesive composition. Further, the present invention relates to a container for a power storage device obtained by processing the packaging material for the power storage device so that the heat-sealed resin film is on the inner surface, and a power storage device using the container for the power storage device.

A secondary battery is a typical power storage device. Due to the rapid growth of electronic devices such as mobile phones and portable personal computers, the demand for secondary batteries such as lightweight and compact lithium-ion batteries has increased. Conventionally, metal cans have been used as the exterior body of the secondary battery, but from the viewpoint of weight reduction and productivity, packaging materials in which plastic films, metal foils, etc. are laminated are becoming mainstream.
As the simplest energy storage device packaging material (hereinafter, also referred to as packaging material), as shown in FIG. 1, the outer layer side resin film (11), the outer layer side adhesive layer (12), and the metal foil (13) are arranged in this order from the outer layer side. , A laminate composed of an inner layer side adhesive layer (14) and a heat-sealing resin film (15). As shown in FIG. 2, the battery container is formed by molding the packaging material so that the outer layer side resin film (11) forms a convex surface and the heat-sealing resin film (15) forms a concave surface (deep drawing molding process). , Overhang molding process, etc.). Then, the battery is manufactured by enclosing and sealing an electrode, an electrolyte solution, or the like on the concave side of the battery container.
Capacitors are also one of the power storage devices, and among them, lithium ion capacitors are a field where the market is expected to grow in the future.

Among the packaging materials for power storage devices, the inner layer side adhesive layer for bonding the metal foil and the heat-sealed resin film is mainly required to have the following performance.
(1) The adhesive strength between the metal foil layer and the heat-sealed resin film is high.
(2) The above-mentioned adhesive layer on the interior side has electrolyte solution resistance. That is, even if the electrolyte is sealed in the battery container, the adhesive strength between the metal foil and the heat-sealed resin film can be maintained.
For example, the electrolyte solution of a lithium battery contains a lithium salt (electrolyte) such as lithium hexafluorophosphate and a solvent such as propylene carbonate, ethylene carbonate, diethyl carbonate and dimethyl carbonate.
When the electrolyte solution contained in the container for the power storage device passes through the heat-sealing resin film and reaches the adhesive layer, the adhesive strength between the heat-sealing resin film and the metal foil is lowered. Further, when water enters the electrolyte solution from the outside of the battery container, a lithium salt such as lithium hexafluorophosphate reacts with water to generate hydrofluoric acid. The generated hydrofluoric acid becomes a factor of deteriorating the heat-sealed resin film and the adhesive layer, and when it passes through the heat-sealed resin film and the adhesive layer and reaches the metal foil, the metal foil is corroded. When metal corrosion occurs, the adhesive strength between the heat-sealed resin film and the metal foil is significantly reduced.
Therefore, the adhesive layer on the interior side, in which the heat-sealed resin film and the metal foil are bonded together, is required to have resistance to the electrolyte itself as well as resistance to substances generated by the action of invaders from the outside of the power storage device on the electrolyte. ..

In order to achieve the performance required as the inner layer side adhesive, Patent Document 1 (Japanese Unexamined Patent Publication No. 2003-123708) contains an adhesive composition containing an acid-modified thermoplastic elastomer (A) and a coupling agent (B). The thing is disclosed. This adhesive composition is used for laminating an unstretched polypropylene film and an aluminum foil on which a nylon film is laminated, and a laminate composed of an unstretched polypropylene film / adhesive layer / aluminum foil / nylon film is used as a packaging material. The secondary battery is disclosed. It is also disclosed that the adhesive composition may contain a tackifier.

Patent Document 2 (WO2004 / 041954) discloses an adhesive composition containing a carboxyl group-containing thermoplastic elastomer (A), a polyolefin polyol (B), a tackifier (C), and a polyfunctional isocyanate (D). Has been done. Then, a laminate in which an aluminum foil or a polyethylene terephthalate film and an unstretched polypropylene film are bonded to each other by using the adhesive is disclosed.
Further, Patent Document 3 (Japanese Unexamined Patent Publication No. 2005-06685) discloses an adhesive containing a polyolefin polyol and a polyfunctional isocyanate curing agent as essential components, and using this adhesive, an aluminum foil and a thermoplastic can be used. A packaging material for a battery case, which is bonded to a resin film and has the thermoplastic resin film as an inner layer, is described.

Patent Document 4 (WO2009 / 087776) discloses an adhesive composition having a polyolefin resin having a carboxyl group having a melting energy of 5 to 15 mJ / mg and a polyfunctional isocyanate.
Further, Patent Document 5 (Japanese Unexamined Patent Publication No. 2010-09203) discloses an adhesive containing a polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound, and uses the adhesive to make an aluminum foil. It is described that the thermoplastic resin film can be bonded together and used as a packaging material for a battery case having the thermoplastic resin film as an inner layer.

Japanese Unexamined Patent Publication No. 2003-123708 WO2004 / 041954 Japanese Unexamined Patent Publication No. 2005-06685 WO2009 / 087776 Japanese Unexamined Patent Publication No. 2010-09203

With the expansion of applications such as in-vehicle and home storage, storage devices are required to have a large capacity, long-term durability and safety. In particular, in in-vehicle applications, it is required to maintain excellent adhesive strength and durability even under conditions exposed to an electrolyte solution. In particular, in a molded packaging material, since the film or adhesive is stretched during molding, a higher level of durability is required so that floating or the like does not occur when immersed in an electrolyte solution.

The adhesives described in Patent Documents 1 to 3 exhibit sufficient adhesive strength, but the crosslinked structure of the adhesive deteriorates due to long-term immersion in an electrolyte solution, and sufficient adhesive strength can be maintained. There is a problem that it cannot be done.
Further, the adhesives described in Patent Documents 4 and 5 have improved durability of the crosslinked structure as compared with Patent Documents 1 to 3, and thus have improved long-term electrolyte solution resistance, but are not yet sufficient. In particular, when the packaging material is molded, there is a problem that the molded portion has a poor appearance or floats due to being immersed in the electrolyte solution for a long period of time.

The present invention has been made in view of the above background, and is an adhesive capable of forming a laminate capable of maintaining a high level of adhesive strength without causing an appearance defect in a molded portion even when immersed in an electrolyte solution for a long period of time. An object of the present invention is to provide a composition. Another object of the present invention is to provide a packaging material for a power storage device, a container for a power storage device, and a power storage device, which are more resistant to an electrolyte solution than before.

As a result of diligent studies by the present inventors, they have found that the problems of the present invention can be solved in the following aspects, and have completed the present invention. The present invention is an adhesive composition containing a polyolefin resin component and a curing agent (C).
The polyolefin resin component has a polyolefin resin (A) having a carboxyl group or an acid anhydride group, a melting point of 55 to 100 ° C., and a weight average molecular weight of 40,000 to 400,000, and a carboxyl group or an acid anhydride group. , A polymer (B) having a weight average molecular weight of 200 to 13000.
The polymer (B) is contained in an amount of 0.2 to 5.0% by weight based on 100% by weight of the total of the polyolefin resin (A) and the polymer (B).
The present invention relates to an adhesive composition, wherein the curing agent (C) has at least one functional group selected from the group consisting of an isocyanate group, an epoxy group, a carbodiimide group, and an aziridine group.

The present invention relates to the adhesive composition, wherein the polymer (B) has an acid value X (mmol / g) of 1.2 to 20.
The present invention relates to the adhesive composition, characterized in that the acid value P (mmol / g) of the polyolefin resin (A) is 0.02 to 1.2.
In the present invention, when the polyolefin resin (A) is i (g), the polymer (B) is j (g), and the functional group of the curing agent is Z (mmol), Z / (P * i + X). * J) The present invention relates to the adhesive composition having a value of 0.3 to 10.

In the present invention, the polymer (B) is a homopolymer (b-1) of an unsaturated carboxylic acid or an acid anhydride thereof, or an unsaturated carboxylic acid or an acid anhydride thereof, an aromatic vinyl compound, and a fat. The present invention relates to the adhesive composition, which is at least one polymer (b-2) selected from the group consisting of a group α-olefin compound and a conjugated diene compound.
The present invention relates to the adhesive composition, wherein the polyolefin resin (A) has a melting point of 65 ° C. to 90 ° C. and a weight average molecular weight of 100,000 to 300,000.

The present invention has an adhesive layer between the metal foil and the heat-sealed resin film layer.
The present invention relates to a laminate, wherein the adhesive layer is formed from the adhesive composition.
The present invention has a surface treatment layer between the metal foil and the adhesive layer.
The present invention relates to the laminate, wherein the surface treatment layer is formed from a treatment agent that reacts with the curing agent (C).
The present invention relates to the laminate, wherein the treatment agent contains at least one selected from the group consisting of a carboxyl group, a hydroxyl group, and an amino group.

The present invention relates to a packaging material for a power storage device that requires an outer layer side resin film, an outer layer side adhesive layer, a metal foil, an inner layer side adhesive layer, and a heat-sealing resin film in this order from the outside.
The present invention relates to a packaging material for a power storage device, wherein the inner layer side adhesive layer is formed from the adhesive composition.

The present invention relates to a container for a power storage device formed of the packaging material for a power storage device, wherein the heat-sealing resin film constitutes the inner surface of the container for the power storage device.
The present invention relates to a power storage device characterized in that the container for the power storage device is used.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an adhesive composition capable of forming a laminate capable of maintaining a high level of adhesive strength without causing an appearance defect in a molded portion even when immersed in an electrolyte solution for a long period of time. Further, it is possible to provide a packaging material for a power storage device, a container for a power storage device, and a power storage device having better resistance to an electrolyte solution than before.

It is a schematic cross-sectional view of one aspect of the packaging material for a power storage device which concerns on embodiment. It is a schematic perspective view of one aspect (tray shape) of the container for power storage device which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described in detail. In the present specification, the description "arbitrary number A to arbitrary number B" means a range larger than the number A and the number A and smaller than the number B and the number B.
As shown in FIG. 1, the packaging material for the power storage device of the present embodiment includes the outer layer side resin film (11), the outer layer side adhesive layer (12), the metal foil (13), the inner layer side adhesive layer (14), and the inner layer side adhesive layer (14). The heat-sealed resin film (15) is sequentially laminated. The outer layer side adhesive layer (12) plays a role of laminating (bonding) the outer layer side resin film (11) and the metal foil (13). The inner layer side adhesive layer (14) plays a role of laminating (bonding) the metal foil (13) and the heat-sealing resin film (15).

The container for the power storage device of the present embodiment is formed by using the packaging material for the power storage device of the present embodiment, and the form thereof is not particularly limited. A preferred example is a tray-shaped container for a power storage device as shown in FIG. In the example of FIG. 2, the heat-sealing resin film (15) is arranged inside the tray, that is, on the concave surface side forming a space for accommodating the electrode, the electrolyte solution, etc., and on the outside of the tray, that is, on the convex surface side. The outer layer side resin film (11) is arranged. In addition to the tray shape, a tubular shape (cylinder, square cylinder, elliptical cylinder, etc.) container for a power storage device is also suitable. These containers for power storage devices are usually obtained by molding a packaging material for power storage devices in a flat state.
The inside of the container for the power storage device, that is, the surface in contact with the electrolyte solution or the like is the heat-sealing resin film (15). The flange portion of the heat-sealing resin film (15) and the flange portion of the heat-sealing resin film (15) constituting another packaging material for a power storage device, or the heat-sealing resin film (15) of another container for a power storage device. The heat-sealing resin films (15) are fused to each other by facing and contacting the flange portion of) and heating, and a power storage device member such as an electrolyte solution and an electrode is sealed.
The container for the power storage device of the present embodiment includes a container for a bag shape (pouch type) as well as a tray shape.

In a container for a power storage device, the side closer to the electrolyte solution is usually referred to as "inner side" and "inner layer", and the side far from the metal foil (13) is referred to as "outer side" and "outer layer". Therefore, even in the packaging material for the power storage device, which is planned to form the container for the power storage device, the side to be close to the electrolyte solution is planned to be far from the "inside", the "inner layer", and the electrolyte solution at the metal leaf (13). Side is called "outside" and "outer layer".

The adhesive composition of the present embodiment is suitably used for forming the inner layer side adhesive layer (14).
The adhesive composition of the present embodiment is sandwiched between the metal foil (13) and the heat-sealed resin film (15), and is combined with a carboxyl group or an acid anhydride group in the polyolefin resin (A). By reacting the carboxyl group or acid anhydride group of the coalescence (B) with the functional group in the curing agent (C) having reactivity with these carboxyl groups or acid anhydride, a dense and strong crosslinked structure is formed. Can be formed. As a result, sufficient adhesive strength can be exhibited, and the adhesive strength can be maintained at a high level even when immersed in a high-temperature electrolyte solution for a long period of time.

<Polyolefin resin component>
The polyolefin resin component has a polyolefin resin (A) having a carboxyl group or an acid anhydride group, a melting point of 55 to 100 ° C., and a weight average molecular weight of 40,000 to 400,000, and a carboxyl group or an acid anhydride group. It contains a polymer (B) having a weight average molecular weight of 200 to 13000. The content of the polymer (B) is 0.2 to 5.0% by weight with respect to 100% by weight of the sum of the polyolefin resin (A) and the polymer (B).

<Polyolefin resin (A)>
The polyolefin resin (A) may have an amorphous moiety because of its solubility in the solvent used for the adhesive composition and the storage stability of the dissolved solution (it can be stably stored without precipitation). preferable. On the other hand, in order to improve the resistance of the electrolyte solution as the adhesive layer in the laminated body, it is preferable to have a crystalline portion, and the balance between the non-crystalline portion and the crystalline portion is important.
The polyolefin resin (A) used in the present embodiment has a weight average molecular weight (Mw) of 40,000 to 400,000 and a melting point of 55 to 100 ° C.

Since the polyolefin resin (A) has a weight average molecular weight of 40,000 to 400,000, it has storage stability as a solution of the polyolefin resin (A) constituting the adhesive composition and an electrolyte as a packaging material for a power storage device. It becomes easy to achieve both solution resistance, heat sealability, and coatability. More preferably, the Mw of the polyolefin resin (A) is 100,000 to 400,000, and even more preferably 100,000 to 300,000.
In other words, if the Mw of the polyolefin resin (A) is less than 40,000, the entanglement of the polymer chains of the polyolefin resin (A) is insufficient, so that the film strength of the adhesive layer is low and the electrolyte solution resistance may be insufficient. .. Further, if Mw is larger than 400,000, the storage stability of the polyolefin resin (A) solution at 25 ° C. may be lowered, or the viscosity of the adhesive solution may be too high to deteriorate the coatability.

Since the polyolefin resin (A) has a melting point of 55 to 100 ° C., the adhesive strength (initially, after immersion in the electrolyte solution) and the heat sealability as a packaging material for a battery can be satisfied in a well-balanced manner.
In other words, if the melting point of the polyolefin resin (A) is less than 55 ° C., the adhesive strength and heat sealability after immersion in the electrolyte solution may decrease. If the melting point is higher than 100 ° C., the adhesive strength (initially, after immersion in the electrolyte solution) may decrease. More preferably, the melting point of the polyolefin resin (A) is 60 to 90 ° C, and even more preferably 65 to 85 ° C.

Further, it is preferable that the melting energy (ΔE) of the polyolefin resin (A) is 15 to 50 (mJ / mg). Within the above range, the adhesive strength and heat-sealing property after immersion in the electrolyte solution are excellent, and the storage stability as the polyolefin resin (A) solution is also excellent. More preferably, the melting energy (ΔE) of the polyolefin resin (A) is 20 to 50 (mJ / mg), and even more preferably 20 to 40 (mJ / mg).

As used herein, "having storage stability" means that 10 g of a resin is added to a mixed solvent of 40 g of toluene, 40 g of methylcyclohexane, and 10 g of methylethylketone, the resin is dissolved by heating to obtain a clear solution, and then the temperature is 4 ° C. for 1 day. It refers to a substance that maintains its fluidity without any change in appearance such as gelation or precipitation when it is allowed to stand and then left to stand at 25 ° C. for 1 day.

Here, the heat sealability will be described.
In addition to adhesive strength and electrolyte solution resistance, packaging materials for power storage devices are also required to have excellent heat sealability.
The heat-sealing resin film (15) (heat seal layer) has a function of enclosing a storage device member such as an electrolyte solution or an electrode in a container for a power storage device. Specifically, the heat-sealed resin film (15) constituting the container for the power storage device is arranged so as to face the heat-sealed resin film (15) of the same or different container for the power storage device (packaging material for the power storage device). The container for the power storage device is sealed by being fused to each other by heat. From the viewpoint of ensuring the heat seal strength (peeling strength between the heat-sealed resin films (15)), heat seal at high temperature and high pressure is preferable.
However, when the adhesive layer (14), in which the heat-sealed resin film (15) and the metal foil layer (13) are bonded, melts or deforms due to the heat and pressure during heat sealing, the electrode terminal and the electrode terminal are formed. There is a possibility that the metal foil layer (13) will be electrically connected. If it conducts, it does not function as a power storage device. Therefore, it is required that the adhesive layer (14) is not melted or deformed by the heat and pressure at the time of heat sealing so that the insulating property between the electrode terminal and the metal foil layer (13) is not impaired by the heat sealing. Be done. It is preferable to use the polyolefin resin (A) having a melting point and melting energy (ΔE) within the above ranges because it is easy to suppress / prevent melting and deformation of the adhesive layer (14) during heat sealing.

The polyolefin resin (A) needs to have a carboxyl group or an acid anhydride group, and it is sufficient to form a strong crosslinked structure by reacting the carboxyl group or the acid anhydride group with the curing agent (C) described later. Adhesive strength and electrolyte solution resistance can be exhibited.
The polyolefin resin (A) preferably has an acid value P (mmol / g) of 0.02 to 1.2 from the viewpoint of excellent adhesiveness and solubility. When it is within the above range, the adhesive strength and durability to the electrolyte solution are excellent due to the cross-linking reaction. In addition, cross-linking shrinkage of the coating film due to excessive cross-linking is unlikely to occur, and the adhesive strength and solubility in a solvent are excellent.

As a method for introducing a carboxyl group or an acid anhydride group, for example, a method of graft-polymerizing an ethylenically unsaturated carboxyl group or an acid anhydride thereof on a polyolefin resin (A1) having no carboxyl group or an acid anhydride group. Alternatively, a method of copolymerizing an olefin monomer with an ethylenically unsaturated carboxylic acid or an acid anhydride thereof can be mentioned. Further, a polyolefin having a carboxyl group can also be obtained by reacting the acid anhydride group of the polyolefin having an acid anhydride group with water, alcohol or the like. Of these, a modified polyolefin resin obtained by graft-polymerizing an ethylenically unsaturated carboxyl group or an acid anhydride thereof on a polyolefin (A1) having no carboxyl group or an acid anhydride group is preferable. The polyolefin resin (A) may be used alone or in any combination of two or more.

The method for graft polymerization of polyolefin is not particularly limited, but for example, the method disclosed in JP-A-11-293216 can be used.

Examples of radical initiators that can be used in graft polymerization of polyolefins include benzoyl peroxide, diisopropyl peroxydicarbonate, g-n-propyl peroxy dicarbonate, dicumyl peroxide, g-t-butyl peroxide, and t-. Known such as butylperoxyneodecanoate, t-butylperoxy2-ethylhexanoate, t-butylperoxyvivarate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and the like. Organic peroxides can be used, and the optimum organic peroxide can be selected from the reaction conditions. These may be used alone or in combination of two or more.

The polyolefin resin (A1) is not particularly limited, and is, for example, a copolymer of an olefin monomer such as ethylene, propylene, 1-butene, butadiene, isoprene, 1-hexene, and 1-octene, and an olefin monomer. Examples thereof include copolymers of each other, copolymers of other monomers, and polymers mainly composed of a hydrocarbon skeleton, such as hydrides and halides of the obtained polymers. Copolymers of olefin monomers are preferred.

As the copolymer of the olefin monomers, a copolymer of 1-butene and another olefin monomer is preferable. As other olefins, ethylene and propylene are preferable, and as a copolymer of 1-butene and another olefin monomer, a binary copolymer of ethylene and 1-butene and a binary of propylene and 1-butene are used. Examples thereof include a copolymer, a ternary copolymer of ethylene, propylene and 1-butene, and a ternary copolymer of propylene and 1-butene is more preferable. The copolymerization ratio is preferably propylene: 1-butene = 10:90 to 90:10 (molar ratio), and more preferably 40:60 to 80:20 (molar ratio). In a copolymer of propylene and 1-butene, when propylene is less than 10 mol%, the melting point may be lower than 55 ° C., and when it is more than 90 mol%, the melting point may be higher than 100 ° C.

The other monomer copolymerizable with the olefin monomer is not particularly limited, and for example,
Aromatic vinyl compounds such as styrene, α-methylstyrene, and indene;
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, Alkyl (meth) acrylate compounds such as behenyl (meth) acrylate;
A (meth) acrylate compound having an alicyclic structure such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate;
A (meth) acrylate compound having an aromatic ring such as benzyl (meth) acrylate;
Hydroxy group-containing (meth) acrylate compounds such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate;
(Meta) acrylate compounds having an amino group such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate;
Acrylamides such as (meth) acrylamide, dimethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, isopropyl (meth) acrylamide, diethyl (meth) acrylamide, and hydroxyethyl (meth) acrylamide;
(Meta) Acrylonitrile, acryloyl morpholine and the like can be mentioned.
Styrene, dodecyl (meth) acrylate, and stearyl (meth) acrylate are preferable from the viewpoint of graft polymerizable property and compatibility with polyolefin.
The ethylenically unsaturated carboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, and itaconic acid. As these ethylenically unsaturated carboxylic acids or acid anhydrides thereof, only one kind may be used, or two or more kinds may be used in combination.

The method for polymerizing the olefin monomer is not particularly limited, but for example, a metal catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst such as the method disclosed in JP-A-07-080948, or (methyl) aluminoxane or the like, if necessary, may be used. A co-catalyst can be added for polymerization.

The weight average molecular weight (Mw) of the polyolefin resin (A) is determined as follows.
The measurement was carried out by the HLC-8220GPC system manufactured by Tosoh Corporation in which two columns of TSKgel superHZM-N were connected under the conditions of a column temperature of 40 ° C., tetrahydrofuran in an eluent, and a flow rate of 0.35 mL / min. The sample was prepared by dissolving 2 mg of the polyolefin resin (A) in 5 mL of tetrahydrofuran. In addition, Mw was calculated in terms of standard polystyrene.
When two or more types of polyolefin resin (A) are used in combination, it means the weight average molecular weight of the entire mixture.

The melting point and melting energy (ΔE) can be determined by DSC measurement according to JIS K7121. Specifically, it is obtained as follows.
The polyolefin resin (A) having a diameter or each side of 0.5 mm or less is used as it is, and if it exceeds 0.5 mm, the polyolefin resin (A) is cut to 0.5 mm or less, and then the polyolefin resin (A) is placed in a container. Add about 10 mg.
It is heated to a temperature about 30 ° C. higher than the melting point at 10 ° C. per minute and then cooled to a temperature about 50 ° C. lower than Tg at 10 ° C. per minute. If no clear Tg is observed, cool to a temperature about 50 ° C. below the melting point. Then, the melting point was determined from the peak top of the peak corresponding to the melting that appeared when the mixture was heated to a temperature about 30 ° C. higher than the melting point at 10 ° C. per minute. Further, ΔE is obtained from the area of the portion where the peak corresponding to melting leaves the baseline and returns to the baseline again.
When two or more types of polyolefin resin (A) are used in combination, the melting point is obtained from the peak top of the peak on the high temperature side, and ΔE is calculated from the sum of all the peak areas obtained by melting.

<Polymer (B)>
The polymer (B) has a carboxyl group or an acid anhydride group, and has a weight average molecular weight of 200 to 13000. The polymer (B) reacts with the curing agent (C) to form a dense crosslinked structure, and by suppressing the swelling and permeation of the electrolyte solution, the polyolefin resin component and the curing agent that do not contain the polymer (B). The resistance to the electrolyte solution can be dramatically improved as compared with the adhesive layer composed only of (C).

The polymer (B) can be obtained, for example, by polymerizing a monomer having an unsaturated carboxylic acid or an acid anhydride thereof, or by copolymerizing the monomer with another monomer.

The monomer having an unsaturated carboxylic acid or an acid anhydride thereof used in the present invention is not particularly limited, but examples having a carboxyl group include acrylic acid, methacrylic acid, and maleic acid. , Fumaric acid, crotonic acid, itaconic acid, and unsaturated fatty acids such as oleic acid and linoleic acid. Examples of having an acid anhydride group include maleic anhydride, itaconic anhydride and the like. Only one kind of these may be used, or two or more kinds may be used in combination.

The other monomer that may be copolymerized with the unsaturated carboxylic acid or its acid anhydride is not particularly limited, and is, for example,
Aromatic vinyl compounds such as styrene, α-methylstyrene, and indene;
Aliphatic α-olefin compounds such as butene, 1-hexene and 1-octene;
Conjugated diene compounds such as butadiene, isoprene, and isobutylene;
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, Alkyl (meth) acrylate compounds such as behenyl (meth) acrylate;
A (meth) acrylate compound having an alicyclic structure such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate;
A (meth) acrylate compound having an aromatic ring such as benzyl (meth) acrylate;
Hydroxy group-containing (meth) acrylate compounds such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate;
(Meta) acrylate compounds having an amino group such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate;
Acrylamides such as (meth) acrylamide, dimethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, isopropyl (meth) acrylamide, diethyl (meth) acrylamide, and hydroxyethyl (meth) acrylamide;
(Meta) Acrylonitrile, acryloyl morpholine and the like can be mentioned.
Only one kind of these monomers may be used, or two or more kinds thereof may be used in combination.

The polymer (B) is not particularly limited and may be a random polymer, a block polymer, or a graft polymer, and at least a part of the acid anhydride groups in these polymers is half-esterified or half. It may be amidated. The half-esterification modified product can be obtained by reacting an acid anhydride with a known alcohol using a known half-esterification reaction method. The half amidation modified product can be obtained by reacting an acid anhydride with a known amine using a known half amidation reaction method.

Further, the polymer (B) may be a dimer or a trimer of an unsaturated fatty acid, and these are also called dimer acids. Further, the unsaturated bond may be hydrogenated. The hydrogenated modified product can be obtained by reacting the unsaturated group of the polymer (B) with hydrogen using a known hydrogenation method.

A preferred example of the polymer (B) is a homopolymer (b-1) of an unsaturated carboxylic acid or an acid anhydride thereof. In addition, a polymer (b-2) of an unsaturated carboxylic acid or an acid anhydride thereof and at least one selected from the group consisting of an aromatic vinyl compound, an aliphatic α-olefin compound, and a conjugated diene compound is also heavy. It is preferable as a coalescence (B). By using the polymers (b-1) and (b-2), the appearance of the molded portion is less likely to deteriorate when immersed in the electrolyte solution for a long period of time. The aliphatic α-olefin compound is preferably an α-olefin having 6 to 30 carbon chains.

Examples of the homopolymer (b-1) of the unsaturated carboxylic acid or its acid anhydride include a maleic acid polymer, a polyacrylic acid, a polymer of an unsaturated fatty acid or a dimer acid or a hydride thereof, a maleic anhydride polymer or Examples thereof include a half esterified product and a half amidated product.

Maleic anhydride is an example of at least one polymer (b-2) selected from the group consisting of unsaturated carboxylic acids or acid anhydrides thereof, aromatic vinyl compounds, aliphatic α-olefin compounds, and conjugated diene compounds. / Styrene copolymer, maleic anhydride / α-olefin copolymer, maleic anhydride / isobutylene copolymer, polybutadiene / maleic anhydride graft polymer, or half esterified or half amidated compounds of these polymers can be mentioned. ..

Known azo compounds and organic peroxides can be used as the radical initiator used when the polymer (B) is produced by a radical reaction.
Examples of azo compounds include 2,2'-azobis (isobutyronitrile), 2,2'-azobis-2,4-dimethylvaleronitrile, and 2,2'-azobis (4-methoxy-2). , 4-Dimethylvaleronitrile), 1,1'-azobis-cyclohexane-1-carbonitrile and the like. Examples of the organic peroxide include benzoyl peroxide, diisopropyl peroxy dicarbonate, di-n-propyl peroxy dicarbonate, dicumyl peroxide, g-t-butyl peroxide, and t-butyl peroxyneodecanoate. Examples thereof include t-butylperoxy2-ethylhexanoate, t-butylperoxyvivarate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and the like. These may be used alone or in combination of two or more. From the viewpoint of excellent reactivity, it is preferable to use an organic peroxide.

Since the polymer (B) has a weight average molecular weight of 200 to 13000, an adhesive having excellent compatibility with the polyolefin resin (A), storage stability as a solution, and curability of the adhesive can be obtained. be able to. More preferably, the weight average molecular weight of the polymer (B) having a carboxyl group or an acid anhydride group is 300 to 10,000.
In other words, if the weight average molecular weight of the polymer (B) is less than 200, the mechanical strength of the adhesive layer may be low and the resistance to the electrolyte solution may be insufficient. On the other hand, if the weight average molecular weight is larger than 13000, the compatibility with the polyolefin resin (A) deteriorates, the storage stability of the adhesive solution deteriorates, or the adhesive film becomes white and the adhesive strength may deteriorate. There is.

The polymer (B) preferably has an acid value X (mmol / g) of 1.2 to 20 from the viewpoint that an adhesive having excellent durability to the electrolyte solution can be obtained.
When it is within the above range, the durability to the electrolyte solution is excellent due to the cross-linking reaction. In addition, it has excellent compatibility with the polyolefin resin (A) and improves the adhesive strength.

The polymer (B) is contained in an electrolyte solution by containing 0.2 to 5% by weight based on 100% by weight of the sum of the polyolefin resin (A) and the polymer (B) having a carboxyl group or an acid anhydride group. Excellent durability can be obtained. More preferably, it is 0.5 to 4% by weight.
In other words, if the content of the polymer (B) is less than 0.2% by weight, the adhesive strength may be lowered during long-term immersion in the electrolyte solution, or the appearance of the molded portion may be poor. On the other hand, if the content is more than 5% by weight, the adhesive film may become too hard, the adhesive strength may be deteriorated, or the resistance to the electrolyte solution may be deteriorated.

<Other polyolefin resins>
In the present embodiment, a polyolefin resin having no carboxyl group or acid anhydride group in addition to the polyolefin resin (A) having a carboxyl group or an acid anhydride group as a polyolefin resin component as long as the effect of the present invention is not impaired. May be used together. The content of the other polyolefin resin is not particularly limited, but is preferably less than 70% by weight, more preferably less than 50% by weight, and even more preferably less than 30% by weight, based on 100% by weight of the polyolefin resin component.

<Curing agent (C)>
Next, the curing agent (C) used in the present invention will be described.
The curing agent (C) can exhibit sufficient adhesive strength by reacting with the carboxyl group or acid anhydride group of the polyolefin resin (A) and the polymer (B) described above, and can be immersed in the electrolyte solution for a long period of time. , It is possible to suppress poor appearance of the molded portion and maintain a high level of adhesive strength.

The curing agent (C) preferably has at least one functional group selected from an isocyanate group, an epoxy group, a carbodiimide group and an aziridine group, and more preferably selected from an isocyanate group and an epoxy group.
By reacting the functional group with the carboxyl group or acid anhydride group of the polyolefin resin (A) and the polymer (B), a crosslinked structure having high durability in the electrolyte solution can be obtained.

The curing agent (C) having an isocyanate group is not limited, but well-known diisocyanates and compounds derived from them can be preferably used.
For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalenedi isocyanate, hexamethylene diisocyanate, bis (4-isocyanate cyclohexyl) methane, or water. Diisocyanates such as anated diphenylmethane diisocyanate and compounds derived from these diisocyanates can be exemplified. Examples of the compound derived from diisocyanate include an isocyanurate form of the diisocyanate, an adduct form, a biuret form, a uretdione form, an allophanate form, a prepolymer having an isocyanate residue (a low polymer obtained from diisocyanate and a polyol), or a compound thereof. Examples include a complex and the like. These may be used alone or in any combination of two or more. Among them, the curing agent (C) containing a structure selected from a biuret body, an isocyanurate body, and a uretdione body is preferable from the viewpoint of excellent durability to an electrolyte solution.

Commercially available products of the curing agent (C) having an isocyanate group include, for example, Coronate HX, HL, L, 2770 manufactured by Nippon Polyurethane Industry Co., Ltd., and Duranate 24A-100, TPA-100, P301-75E manufactured by Asahi Kasei Chemicals Co., Ltd. , TSE-100, MFA-75B, MHG80-B, Mitsui Chemicals Co., Ltd. Takenate D-110N, D-120N, D-127N, D-160N, D-170N, D-165N, D-178N, etc. Be done.

The curing agent (C) having an epoxy group is not limited, but a well-known epoxy compound can be preferably used.
For example, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, N, N-bis (2,3-epoxypropyl) aniline, 2-methyl-N. , N-bis (2,3-epoxypropyl) aniline, N, N-diglycidylaniline, N, N-diglycidyl-2-methylbenzeneamine, N, N, N', N'-tetrakis (2,3- Epoxypropyl) -1,4-phenylenediamine, N, N, N', N'-tetrakis (oxylan-2-ylmethyl) -4,4'-methylenebisaniline, N, N-diglycidyl-4- (glycidyloxy) ) Epoxy compounds having an aromatic amino group such as aniline, epoxy compounds having a triazine skeleton such as 2,4,6-tri (glycidyloxy) -1,3,5-triazine, and the like can be mentioned. These may be used alone or in any combination of two or more.

Commercially available products of the curing agent (C) having an epoxy group include, for example, jER-828, jER-834, jER-1001, jER-1002, jER-1004, jER-604, and jER-630 manufactured by Mitsubishi Chemical Corporation. , ADEKA Co., Ltd. Adecaledin EP-4100, EP-4340, EP-4901, EP-4950, EP-4000, EP-4005, EP-3950S, EP-3980S, Nagase Chemtex Co., Ltd. Denacol EX-611 , EX614, EX-411, EX-411, R-45EPT, TEPIC-G, TEPIC-S, TEPIC-SP, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC manufactured by Nissan Chemical Co., Ltd. -VL, TETRAD-X, TETRAD-C manufactured by Mitsubishi Gas Co., Ltd. and the like can be mentioned.

The curing agent (C) having a carbodiimide group is not limited, but a well-known carbodiimide compound can be preferably used. For example, a polycondensate of a well-known diisocyanate and a derivative exemplified by a curing agent having an isocyanate group can be mentioned. These may be used alone or in any combination of two or more.

Examples of commercially available products of the curing agent (C) having a carbodiimide group include carbodilites V-01, V-03, V-05, V-07, and V-09 manufactured by Nisshinbo Chemical Co., Ltd.

The curing agent (C) having an aziridine group is not limited, but a well-known aziridine compound can be preferably used. For example, N, N'-hexamethylene-1,6-bis (1-aziridinecarboxyamide), N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxyamide), trimethylpropan-tri- β-aziridinyl propionate), N, N'-toluene-2,4-bis (1-aziridinecarboxyamide), triethylene melamine, trimethylpropan-tri-β (2-methylaziridine) propionate, bis Examples thereof include isophthaloyl-2-methylaziridine, tri (1-aziridinyl) phosphine oxide, and tris (2-methyl-1-aziridinyl) phosphine oxide. These may be used alone, or may be used in any combination of two or more.

Examples of commercially available products of the curing agent (C) having an aziridine group include Chemitite PZ-33 manufactured by Nippon Shokubai Co., Ltd., CROSSLINKER CL-427 manufactured by Mutual Yakuko Co., Ltd., and the like.

The polyolefin resin (A) contained in the adhesive composition is igram (g), the polymer (B) having a carboxyl group or an acid anhydride group is jgram (g), and the functional group of the curing agent (C) is used. When Z mmol is used, Z / (P * i + X * j) (P: acid value of polyolefin resin (A), X: acid value of polymer (B)) is 0.3 to 10. It is more preferable that the curing agent (C) is contained in the range and is contained in the range of 0.5 to 7. In this specification, "*" represents a multiplication symbol.
When the range is in the range of 0.3 to 10, the amount of the epoxy group with respect to the active hydrogen derived from the carboxyl group in the polyolefin resin (A) is suitable, so that the crosslinked structure provides cohesive strength, adhesive strength, and durability to the electrolyte solution. Excellent in sex. Further, the durability to the electrolyte solution is improved because the unreacted curing agent (C) is less likely to be present in an excessive amount.

The adhesive of the present embodiment can further contain a silane coupling agent. Examples of the silane coupling agent include trialkoxysilane having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane, 3-aminopropyltriethoxysilane, and N- (2-aminoethyl) 3-aminopropyltrimethoxysilane. It has a glycidyl group such as trialkoxysilane having an amino group such as 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane. Examples thereof include trialkoxysilane. The amount of the silane coupling agent added is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the solid content of the adhesive. Thereby, the adhesive strength with the metal foil can be increased.

In addition, the adhesive of the present embodiment can further contain an oxygen acid of phosphorus or a derivative thereof. Among the oxygen acids of phosphorus or derivatives thereof, the oxygen acid of phosphorus may be any one having at least one free oxygen acid, for example, hypophosphoric acid, phosphoric acid, orthophosphoric acid, the following. Examples thereof include phosphoric acids such as phosphoric acid, and condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid. Examples of the derivative of the oxygen acid of phosphorus include those in which the oxygen acid of phosphorus is partially esterified with alcohols while leaving at least one free oxygen acid. Examples of these alcohols include fatty alcohols such as methanol, ethanol, ethylene glycol and glycerin, and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol and fluoroglusinol. The oxygen acid of phosphorus or a derivative thereof may be used in combination of two or more. The amount of phosphorus oxygen acid or a derivative thereof added is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, based on the solid content of the adhesive, and is 0.1. It is particularly preferably ~ 1% by mass. This makes it possible to increase the adhesive strength after immersion in the electrolyte solution.

The adhesive of the present invention can further contain an epoxy phosphate resin. In the epoxy phosphoric acid ester resin, the epoxy group of the epoxy resin reacts with phosphoric acid, the epoxy group is opened, and the epoxy resin portion and the phosphoric acid portion are bonded by a phosphoric acid ester bond. This makes it possible to increase the adhesive strength after immersion in the electrolyte solution.

A preferable epoxy phosphate resin is a compound represented by the following general formulas (1) and (2).

General formula (1)

General formula (2)

Examples of the epoxy resin that reacts with phosphoric acid include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, bisphenol AD type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, and alicyclic epoxy. Examples thereof include resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, heterocyclic epoxy resins, diarylsulfone type epoxy resins, hydroquinone type epoxy resins and modified products thereof.

As the epoxy phosphate ester resin, a commercially available product can also be used. Specifically, URAD-DD79 (manufactured by DSM Japan) is preferable. Further, an epoxy phosphate resin having the same characteristic values as the above-mentioned URAD-DD79 is also suitable.

The adhesive of the present embodiment can contain catechol or a derivative thereof. Specific examples thereof include catechol, t-butylcatechol, adrenaline, noradrenaline, dopamine, and nordihydroguayaletic acid. Thereby, the adhesive strength with the metal foil can be increased.

The adhesive composition of the present embodiment may contain an organic solvent. The organic solvent is not particularly limited, but the material used in the present adhesive composition can be dissolved as a single solvent or a mixed solvent, the reactivity with the curing agent (C) is inert, and the drying step at the time of applying the adhesive. Those that can be volatilized and removed by overheating in the above are preferable. Specific examples of these solvents include aromatic organic solvents such as toluene and xylene;
Aliphatic organic solvents such as n-hexane and n-heptane;
Alicyclic organic solvents such as cyclohexane and methylcyclohexane;
Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone;
Ester solvents such as ethyl acetate and butyl acetate;
Alcohol-based solvents such as ethanol, methanol, n-propanol, 2-propanol, butanol, and hexanol;
Ether-based solvents such as diisopropyl ether, butyl cellosolve, tetrahydrofuran, dioxane, butyl carbitol;
Glycol ether solvents such as diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, and propylene glycol monomethyl ether;
Examples thereof include glycol ester solvents such as ethylene glycol monomethyl ether acetate, proprene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate, which may be used alone or in combination of two or more.
Among these, from the viewpoint of storage stability of the solution of the polyolefin resin (A), a combination of an aromatic organic solvent and a ketone solvent, a combination of an aromatic organic solvent and an alcohol solvent, and an alicyclic organic solvent It is preferable to use a ketone solvent in combination and an alicyclic organic solvent and an alcohol solvent in combination.

In the adhesive composition of the present embodiment, known additives such as a tackifier and a plasticizer may be blended, if necessary, as long as the effects of the invention are not impaired.
Examples of the tackifier that can be used in the present embodiment include polyterpene resin, rosin resin, aliphatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, styrene resin, hydrogenated petroleum resin and the like. It is used for the purpose of improving adhesive strength. These may be used alone or in any combination of two or more.
Examples of the plasticizer used in the present embodiment include liquid rubbers such as polyisoprene and polybutene, and procel oil.

The adhesive composition of the present embodiment is suitably used for laminating a metal foil (13) and a heat-sealing resin film (15).

<Metal leaf>
Examples of the metal of the metal foil (13) include aluminum, copper, nickel, steel, and stainless steel (SUS). These metal foils may be subjected to various surface treatments. Examples of surface treatments include physical treatments such as sandblasting and polishing treatments, degreasing treatments by vapor deposition, etching treatments, and surface treatments such as primer treatments for applying a coupling agent or a coating agent.
The treatment agent for forming the surface treatment layer preferably contains a functional group that reacts with the functional group in the curing agent (C), and more preferably at least one selected from the group consisting of a carboxylic acid, a hydroxyl group and an amino group. It preferably contains the functional group of the species. The amino group referred to here is a primary amine, a secondary amine, and an imino group. By providing the surface treatment layer containing such a functional group on the surface of the metal foil (13), when the adhesive composition is heat-cured, the epoxy group in the adhesive layer and the functional group in the surface treatment layer are used. Is preferable because the initial adhesive strength is high and a laminate having excellent electrolyte solution resistance can be obtained.

<Heat fusion resin film>
The heat-sealed resin film (15) is not particularly limited, but is preferably a polyolefin-based film, and is selected from the group consisting of polyethylene, polypropylene, olefin-based copolymers, acid-modified products thereof, and ionomers. It is preferably an unstretched film made of at least one type of thermoplastic resin. The thickness of the heat-sealed resin film is not particularly limited, but is preferably 20 to 150 μm.

A laminate made by using the adhesive composition of the present embodiment can be obtained, for example, as follows.
The adhesive composition of the present embodiment is applied to one surface of the metal foil (13) (or the heat-sealed resin film (15)), the solvent is volatilized (dried), and the uncured adhesive layer is applied. Is formed, and a heat-sealing resin film (or metal foil) is placed on the surface of the uncured adhesive layer under pressure at 60 to 150 ° C., and then allowed to stand at 40 to 80 ° C. for about 1 to 10 days. Then, the adhesive layer is sufficiently cured (also referred to as aging), and the metal foil and the heat-sealing resin film are bonded to each other to obtain a laminated body.
A general coating machine such as a comma coater can be used for coating the adhesive composition. The thickness (amount) of the cured adhesive layer during drying and curing is preferably about ^{0.5 to 10 g / m 2.}

The packaging material for a power storage device of the present embodiment has an outer layer on the other surface of the metal foil (13) (a surface not in contact with the inner layer side adhesive layer (14) formed from the adhesive composition of the present embodiment). The outer layer side resin film layer (11) can be formed via the side adhesive layer (12).
The outer layer side resin film layer (11) is laminated on the metal foil (13) in advance using an adhesive composition (which may be the same as or different from the adhesive composition of the present embodiment). After obtaining a laminate of the metal foil (13) and the heat-sealed resin film (15) using the adhesive composition of the present embodiment, the outer layer side is adhered to the metal foil (13). The outer layer side resin film layer (11) may be laminated via the agent layer (12).
Examples of the outer layer side resin film layer (11) used include stretched films such as polyester resin and polyamide resin (nylon). The outer layer side resin film layer (11) is located on the outside where the laminate is used as a packaging material for a power storage device and does not come into contact with the electrolyte solution when forming a container for the power storage device.

The container for the power storage device of the present embodiment is molded by using the above-mentioned packaging material for the power storage device so that the outer layer side resin film layer (11) forms a convex surface and the heat-sealing resin film (15) forms a concave surface. Can be obtained.
The "concave surface" as used herein is a surface having a recess that can accommodate an electrolyte solution when a flat battery packaging material is molded into a tray shape as shown in FIG. The term "convex surface" as used herein means the self-back surface (opposite side surface, back side surface) of the surface having the recess.

A power storage device such as a secondary battery includes a battery body, a plurality of terminals bonded to the positive electrode and the negative electrode of the battery body, a battery container, and an electrolyte solution. The battery container is obtained from a laminate obtained by laminating a metal foil (13) and a heat-sealing resin film (15) via an adhesive layer (14) formed from the adhesive composition of the present invention. The heat-sealed resin film comes into contact with the electrolyte solution.

The electrolyte solution begins to permeate from the heat-sealed resin film (15) toward the metal foil (13), whereas the adhesive layer (14) formed from the adhesive composition of the present invention becomes resistant to the electrolyte solution. Since it is excellent, the adhesive strength between the heat-sealed resin film and the metal foil does not decrease, and problems such as liquid leakage do not occur.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of rights of the present invention at all. In addition, each evaluation in an Example followed the following method. In the examples,% indicates mass% and parts indicate mass parts.
<Quantification of acid value>
The weighed sample a (g) was dissolved in refluxed xylene, cooled to room temperature, and then titrated with phenolphthalein as an indicator and 0.1 M of ethanolic potassium hydroxide for quantification. The end point of the titration was when the coloration of the indicator remained for 10 seconds. Assuming that the titration amount is b (mL), the acid value can be calculated from the following formula.
Acid value = 0.1 * b / a

<Weight average molecular weight>
By the HLC-8220GPC system manufactured by Tosoh Corporation in which two columns of TSKgel superHZM-N were connected, the eluent was tetrahydrofuran, the column temperature was 40 ° C., and the measurement was performed under the conditions of a flow rate of 0.35 mL / min. The sample was prepared by dissolving 2 mg of the polyolefin resin (A) in 5 mL of tetrahydrofuran. The weight average molecular weight was calculated in terms of standard polystyrene.

<Melting point, melting energy (ΔE)>
The melting point and ΔE can be determined by DSC measurement according to JIS K7121. The specific measurement method is as described above.

<Copolymerization composition ratio>
The copolymer composition ratio of polyolefin was determined by the measurement of ¹³ C using NMR (JNM-LA400) manufactured by JEOL Ltd.
20 mg of the sample was dissolved in 1 mL of deuterated chloroform and measured. The methine group derived from propylene is contained in 25-30 ppm, and the methine group derived from 1-butene is contained in 30-35 ppm. The copolymer composition ratio was determined from the integral ratio of each peak.

<Preparation of polyolefin resin (A)>
<Manufacturing example 1>
As a polyolefin polymerization reaction, 250 mL of purified toluene, 0.5 mg of methylaluminoxane in terms of Al atoms, dimethylsilyl-bis- (4,5,6,7,8-pentahydroazulene) in a glass autoclave with an internal volume of 500 mL substituted with nitrogen. -2-Il) Zirconium dichloride was charged with 1.25 μg atoms in terms of Zr atoms, and the temperature was raised to 20 ° C. Subsequently, while supplying propylene at a constant rate of 100 L / hr, 1-butene monomer was continuously supplied so as to maintain a constant pressure of 1.32 MPa at 20 ° C., and polymerization was started. After the polymerization was carried out at 20 ° C. for 8 hours, isopropanol was added to terminate the polymerization. The obtained polymer solution was added to a large amount of methanol to precipitate the polymer. The precipitated polymer was filtered and dried to obtain a polyolefin copolymerized at propylene / 1-butene = 72/28 (molar ratio).
As a monomer graft reaction to polyolefin, 380 g of polyolefin obtained in a glass reaction vessel having an internal volume of 2 L, 600 g of toluene, and 16 g of maleic anhydride as a graft monomer were charged and dissolved by heating under a nitrogen stream to set the solution temperature to 100. It was set to ° C. After stirring for 1 hour, 4 g of tert-butylperoxy (2-ethylhexanoate) was added and the reaction was continued at that temperature for 4 hours. The polymer solution thus obtained was added to a large amount of methanol with stirring to precipitate a polymer. The precipitated polymer was filtered, washed with methanol several times, and dried to obtain a polyolefin resin (A1). It was confirmed from the GPC measurement that the components other than the polyolefin resin (A1) could be removed from the obtained polyolefin resin (A1).
The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A1) were 186000, 0.018 mmol / g, 76 ° C., and 30 mJ / mg, respectively.

<Manufacturing example 2>
During the polyolefin polymerization reaction, propylene was supplied at a flow rate of 20 L / hr, and methylaluminoxane was 0.4 mg in terms of Al atom, dimethylsilyl-bis- (4,5,6,7,8-pentahydroazulen-2-). Il) Zyroxide dichloride using 1 μg atom in terms of Zr atom, 388 g of polyolefin during the monomer graft reaction to polyolefin, 10 g of maleic anhydride as the graft monomer, and tert-butylperoxy (2-ethylhexa) as the radical initiator. A polyolefin resin (A2) copolymerized with propylene / 1-butene = 19/81 (molar ratio) was obtained in the same manner as in Production Example 1 except that 2 g of Noate) was used.
The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A2) were 290000, 0.06 mmol / g, 58 ° C., and 27 mJ / mg, respectively.

<Manufacturing example 3>
Propylene was supplied at a flow rate of 150 L / hr during the polyolefin polymerization reaction, 379 g of polyolefin was used during the monomer graft reaction with polyolefin, 15 g of maleic anhydride as the graft monomer, 4 g of lauryl methacrylate, and tert-butyl as the radical initiator. A polyolefin resin (A3) copolymerized with propylene / 1-butene = 86/14 (molar ratio) was obtained by the same method as in Production Example 1 except that 2 g of peroxy (2-ethylhexanoate) was used. rice field.
The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A3) were 194000, 0.12 mmol / g, 92 ° C., and 28 mJ / mg, respectively.

<Manufacturing example 4>
Propylene is supplied at a flow rate of 85 L / hr during the polyolefin polymerization reaction, 350 g of polyolefin during the monomer graft reaction to polyolefin, 40 g of maleic anhydride as the graft monomer, and tert-butylperoxy (2-) as the radical initiator. A polyolefin resin (A4) copolymerized with propylene / 1-butene = 67/33 (molar ratio) was obtained in the same manner as in Production Example 1 except that 10 g of (ethylhexanoate) was used.
The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A4) were 165000, 0.3 mmol / g, 74 ° C., and 28 mJ / mg, respectively.

<Manufacturing example 5>
2. During the polyolefin polymerization reaction, methylaluminoxane was 1.5 mg in terms of Al atom, and dimethylsilyl-bis- (4,5,6,7,8-pentahydroazulen-2-yl) zirconium dichloride was converted into Zr atom. Except for using 5 μg atoms, 380 g of polyolefin during the monomer graft reaction to polyolefin, 18 g of maleic anhydride as the graft monomer, and 2 g of tert-butylperoxy (2-ethylhexanoate) as the radical initiator. A polyolefin resin (A5) copolymerized with propylene / 1-butene = 73/27 (molar ratio) was obtained in the same manner as in Production Example 1.
The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A5) were 60,000, 0.12 mmol / g, 76 ° C., and 26 mJ / mg, respectively.

<Manufacturing example 6>
During the polyolefin polymerization reaction, methylaluminoxane was added to 0.25 mg in terms of Al atom, and dimethylsilyl-bis- (4,5,6,7,8-pentahydroazulen-2-yl) zirconium dichloride was added to 0. Except for using 5 μg atoms, 380 g of polyolefin during the monomer graft reaction to polyolefin, 18 g of maleic anhydride as the graft monomer, and 2 g of tert-butylperoxy (2-ethylhexanoate) as the radical initiator. A polyolefin resin (A6) copolymerized at propylene / 1-butene = 72/28 (molar ratio) was obtained in the same manner as in Production Example 1.
The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A6) were 376000, 0.11 mmol / g, 77 ° C., and 26 mJ / mg, respectively.

<Manufacturing example 7> (for comparison)
As the polyolefin resin (A7), Kuraray LIR-403 (maleated polyisoprene) manufactured by Kuraray Co., Ltd. was used.
The Mw and acid value P of the polyolefin resin (A7) were 45,000 and 0.1 mmol / g, respectively, and did not have a melting point.

<Preparation of polymer (B)>
<Manufacturing example 8>
As the polymer (B1), SMA2625 (a half esterified product of a styrene / maleic anhydride copolymer) manufactured by Clay Valley Co., Ltd. was used.
The Mw and acid value X of the polymer (B1) were 9000, 3.9 mmol / g, respectively.

<Manufacturing example 9>
As the polymer (B2), Diacarna 30 (maleic anhydride / α-olefin copolymer having 20 to 28 carbon chains) manufactured by Mitsubishi Chemical Corporation was used.
The Mw and acid value X of the polymer (B2) were 9000 and 1.3 mmol / g, respectively.

<Manufacturing example 10>
As the polymer (B3), John Krill 68 (styrene / acrylic acid copolymer) manufactured by BASF was used.
The Mw and acid value X of the polymer (B3) were 10,000 and 3.5 mmol / g, respectively.

<Manufacturing example 11>
As the polymer (B4), Croda's Pripol 1009 (hydrogenated dimer acid of unsaturated fatty acid) was used.
The Mw and acid value X of the polymer (B4) were 900 and 2.4 mmol / g, respectively.

<Manufacturing example 12>
Isovan 600 (maleic anhydride / isobutylene copolymer) manufactured by Kuraray Co., Ltd. was used as the polymer (B5).
The Mw and acid value X of the polymer (B5) were 7000 and 14.1 mgKOH / g, respectively.

<Manufacturing example 13>
As the polymer (B6), Ricon 130MA20 (maleic acid graft-modified polybutadiene) manufactured by Clay Valley Co., Ltd. was used.
The Mw and acid value X of the polymer (B6) were 6500 and 2.1 mmol / g, respectively.

<Manufacturing example 14>
As the polymer (B7), SMA3940 (a half esterified product of a styrene / maleic anhydride copolymer) manufactured by Cliver Co., Ltd. was used.
The Mw and acid value X of the polymer (B7) were 11000 and 1.9 mmol / g, respectively.

<Manufacturing example 15>
In a 1 L four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, 160 g of methyl ethyl ketone and 38.9 g of maleic anhydride were charged, and a water bath at 90 ° C. was used while introducing nitrogen gas. The mixture was heated and stirred. The reaction was carried out by adding 1.1 g of t-butyl peroxyvivalate while maintaining the reflux state and heating and stirring for 4 hours. The solution thus obtained was sufficiently dried after distilling off the solvent and unreacted maleic anhydride using an evaporator to obtain a maleic acid polymer. The polymer thus obtained is referred to as a polymer (B8).
The Mw and acid value X of the polymer (B8) were 250 and 16.9 mmol / g, respectively.

<Manufacturing example 16>
150 g of methyl ethyl ketone was charged into a 1 L four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, and heating and stirring were performed using a water bath at 90 ° C. while introducing nitrogen gas. A solution obtained by uniformly mixing 15 g of methacrylic acid, 40 g of lauryl methacrylate, 45 g of methyl methacrylate, and 1.5 g of t-butylperoxyvivarate while maintaining the reflux state over 2 hours using a dropping funnel. The reaction was carried out by dropping. After continuing heating and stirring for 2 hours after the completion of the dropping, 0.15 g of t-butylperoxyvivarate was added, and heating and stirring was further performed for 3 hours. The resin solution thus obtained was concentrated using an evaporator and dried to obtain a polymer (B9).
The Mw and acid value X of the polymer (B9) were 9000 and 17.0 mmol / g, respectively.

<Preparation of main agent>
The polyolefin resin (A) and the polymer (B) are placed in a glass container so that the content of the polymer (B) with respect to 100% by weight of the sum of the polyolefin resin (A) and the polymer (B) becomes the value shown in Table 1. A total of 20 g was blended and dissolved in 80 g of a mixed solvent of methylcyclohexane / methylethylketone = 7/3 (weight ratio) to prepare a resin solution having a solid content concentration of 20%, which was used as the main agent solution.

<Preparation of curing agent>
<Preparation example 1 of curing agent>
In a glass container, 50 g of Duranate TPA-100 (trimer of hexamethylene diisocyanate, amount of functional group of isocyanate group 5.2 mmol / g) manufactured by Asahi Kasei Chemicals Co., Ltd. and 50 g of ethyl acetate are added and dissolved to dissolve the solid content. A solution having a concentration of 50% was obtained. This is used as a curing agent (C1).

<Preparation example 2 of curing agent>
50 g of jER-604 (tetraglycidyldiaminodiphenylmethane, functional group amount of epoxy group 10.0 mmol / g) manufactured by Mitsubishi Chemical Corporation and 50 g of ethyl acetate are added to a glass container and dissolved to achieve a solid content concentration of 50%. Solution was obtained. This is used as a curing agent (C2).

<Preparation example 3 of curing agent>
In a glass container, a condensate of carbodilite V-05 (1,3-bis (2-isocyanato2-propyl) benzene) manufactured by Nisshinbo Chemical Co., Ltd., a carbodiimide group with a functional group amount of 3.8 mmol / g, and an isocyanate group. A solution having a solid content concentration of 50% was obtained by adding 50 g of a functional group amount of 1.9 mmol / g) and dissolving the mixture. This is used as a curing agent (C3).

<Preparation example 4 of curing agent>
In a glass container, 50 g of Chemitite PZ-33 (tris (1-aziridine propionic acid) 1,1,1-propanetriyltrismethylene, functional group amount of aziridine group 6.3 mmol / g) manufactured by Nippon Catalyst Co., Ltd., By adding 50 g of ethyl acetate and dissolving it, a solution having a solid content concentration of 50% was obtained. This is used as a curing agent (C4).

<Making metal leaf>
<Production example 1 of treated aluminum>
3.8 parts of polycarboxylic acid resin (Acryset, EMN-260E, manufactured by Nippon Catalyst Co., Ltd.), 2 parts of orthophosphoric acid, and 4 parts of chromium (III) fluoride are dissolved in 990 parts of distilled water, and further, oxazoline. A treatment agent 1 having a solid content concentration of 1% was prepared by dissolving 0.2 part of a group-containing polymer (Epocross WS-700, manufactured by Nippon Catalyst Co., Ltd.).
A treatment liquid 1 is applied to one surface of a degreased aluminum foil (40 μm) so that a dry coating amount is 50 mg / m ^2, and the surface treatment layer is derived from a polycarboxylic acid resin by drying at 150 ° C. AL-1 having a carboxyl group of

<Production example 2 of treated aluminum>
By dissolving 1 part of the amination phenol polymer, 0.5 part of chromium (III) fluoride, and 2 parts of phosphoric acid in 346.5 parts of distilled water, a treatment agent 2 having a solid content concentration of 1% was prepared. did.
The treatment liquid 2 is applied to one surface of the degreased aluminum foil (40 μm) so that the dry coating amount is 50 mg / m ^2, and the surface treatment layer is dried at 150 ° C. to obtain an amination phenol polymer. AL-2 having a derived hydroxyl group was obtained.

<Production example 3 of treated aluminum>
A cerium oxide sol (treatment agent 3) having a solid content concentration of 10% was obtained by mixing 9.1 parts of cerium oxide, 0.9 parts of sodium phosphate salt, and 90 parts of distilled water.
A phosphoric acid-derived hydroxyl group is applied to the surface-treated layer by applying the treatment liquid 3 to one surface of the degreased aluminum foil (40 μm) so that the dry coating amount is 80 mg / m ^{2 and drying at 200 ° C.} AL-3 having the above was obtained.

<Production example 4 of treated aluminum>
A treatment agent 4 having a solid content concentration of 5% was prepared by mixing 4.5 parts of polyethyleneimine, 0.5 parts of an acrylic-isopropenyloxazoline copolymer, and 95 parts of distilled water.
The surface of the treated aluminum AL-3 is further ^{coated with the treatment liquid 4 so as to have a dry coating amount of 25 mg / m 2,} and dried at 200 ° C. to have an amino group derived from polyethyleneimine in the surface treatment layer. AL-4 was obtained.

<Examples 1 to 23, Comparative Examples 1 to 4>
Various main agent solutions and curing agent solutions were mixed so that the values of Z / (P * i + Z * j) shown in Table 2 were obtained, and diluted with a mixed solvent of methylcyclohexane / methylethylketone = 7/3 (weight ratio). An adhesive composition was prepared by adjusting the solid content concentration to 15%. However, in Example 23, the viscosity was high at a solid content concentration of 15%, so the adhesive composition was prepared by adjusting the solid content to 10%.
A laminate of the metal foil and the unstretched polypropylene film shown in Table 2 was prepared according to the method described later, and the initial adhesive strength, the adhesive strength after immersion in the electrolyte solution, and the presence or absence of changes in the appearance of the molded portion after immersion in the electrolyte solution were evaluated.

The symbols in Tables 1 and 2 are as follows.
LMA: Lauryl Methacrylate MMA: Methyl Methacrylate MAA: Methacrylic Acid

<Performance test>
(Making nylon / treated aluminum laminated film)
A urethane-based dry laminate adhesive (“AD502 / CAT10” manufactured by Toyo Morton Co., Ltd.) ^{was applied to the untreated surface of the treated aluminum so as to have a dry coating amount of 4 g / m 2,} and dried at 100 ° C. for 1 minute. After that, a biaxially stretched nylon film having a thickness of 25 μm was laminated. Then, the obtained laminate was cured (aged) at 60 ° C. for 7 days to sufficiently cure the adhesive. The nylon / treated aluminum laminated film is hereinafter referred to as "ONY / AL laminated film".

(Making nylon / treated aluminum / unstretched polypropylene laminated film)
The adhesives of Examples and Comparative Examples were applied to the aluminum-treated surface of the ONY / AL laminated film so as to have a dry coating amount of 2 g / m ² , dried at 100 ° C. for 1 minute, and then 30 μm thick. Unstretched polypropylene film (CPP) was laminated. Then, the obtained laminate was aged at 40 ° C. for 7 days to sufficiently cure the adhesive. The nylon / treated aluminum / CPP laminated film thus obtained is hereinafter referred to as "ONY / AL / CPP laminated film".

(Preparation of treated aluminum / unstretched polypropylene laminated film)
Each adhesive was applied to the treated surface of the treated aluminum so as to have a dry coating amount of 2 g / m ² , dried at 100 ° C. for 1 minute, and then CPP having a thickness of 30 μm was bonded. Then, the obtained laminate was aged at 40 ° C. for 7 days to sufficiently cure the adhesive. The treated aluminum / CPP laminated film thus obtained is hereinafter referred to as "AL / CPP laminated film".

[Initial adhesive strength (before immersion in electrolyte solution)]
The Al / CPP laminated film was allowed to stand in an environment of 25 ° C. and 65% humidity for 6 hours, then cut into a size of 200 mm × 15 mm, respectively, and a tensile tester was used according to the test method of ASTM-D1876-61. The T-type peeling test was performed at a load rate of 100 mm / min in an environment of 25 ° C. and a humidity of 65%. The peel strength (N / 15 mm width) between the aluminum foil / CPP is shown by the average value of 5 test pieces. The results were judged according to the following criteria.
⊚: Excellent in practical use: 7N or more 〇: Practical range: 5N or more and less than 7N ×: Not practical: Less than 5N

[Adhesive strength after immersion in electrolyte solution]
A similar test piece used in the initial adhesive strength test was dissolved in an electrolyte solution [lithium hexafluorophosphate in ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio)) and 1 mol / l 6 It was immersed in a solution of lithium fluoride phosphate] at 85 ° C. for 7 days. Then, the test piece was taken out, washed with running water for about 10 minutes, and after sufficiently wiping off the water with a paper wiper, the adhesive strength of the test piece was measured in the same manner as the adhesive strength before the immersion test. The measurement result was judged according to the following criteria.
⊚: Excellent in practical use: 7N or more 〇: Practical range: 5N or more and less than 7N ×: Not practical: Less than 5N

[Presence / absence of change in appearance of molded part after immersion in electrolyte solution]
The ONY / AL / CPP laminated film is made into a blank shape of 110 mm × 180 mm, and a straight mold (the punch shape is 60 mm on the long side, 45 mm on the short side, corner R = 1 to 2 mm, punch shoulder R = 1 mm, die shoulder R). = 0.5 mm), one-stage overhanging was performed so that the molding height was 5 mm. Next, the molded laminated film was dissolved in an electrolyte solution [lithium hexafluorophosphate in ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio)), and 1 mol / l lithium hexafluorophosphate was dissolved. It was immersed in a solution] at 85 ° C. for 7 days. Then, the molded laminated film was taken out, washed with running water for about 10 minutes, and after sufficiently wiping off the water with a paper wiper, the presence or absence of a change in the appearance of the AL / CPP interface at the molded site was visually evaluated. The results were judged according to the following criteria.
◎: Excellent for practical use: No floating / whitening 〇: Practical range: No floating, but whitening ×: Not practical: With floating

As shown in Table 3, since Comparative Example 1 does not contain the polymer (B) having a carboxyl group or an acid anhydride group, the degree of cross-linking of the adhesive is insufficient, and the molded portion floats when immersed in the electrolyte solution for a long period of time. I have.

In Comparative Example 2, since the polymer (B) was contained in an amount of more than 5% by weight based on 100% by weight of the sum of the polyolefin resin (A) and the polymer (B), the adhesive film became too hard. As a result, the adhesive strength and the appearance of the molded part deteriorated when immersed in the electrolyte solution.

In Comparative Example 3, since the melting point of the polyolefin resin (A) was not in the range of 55 to 100 ° C., the cohesive force as an adhesive was insufficient, and sufficient initial adhesive strength could not be obtained.

In Comparative Example 4, since the curing agent (C) is not contained, a crosslinked structure with the polyolefin resin (A) and the polymer (B) is not formed, the cohesive force as an adhesive is insufficient, and sufficient initial adhesive strength is obtained. Was not obtained.

On the other hand, Examples 1 to 23 shown in Table 3 have a weight average molecular weight of 40,000 to 400,000, a melting point of 55 to 100 ° C., and a carboxyl group or an acid anhydride group as the polyolefin resin (A). As the polyolefin resin and the curing agent (C), the curing agent and the polymer (B) having at least one functional group selected from an isocyanate group, an epoxy group, a carbodiimide group and an aziridine group have a weight average molecular weight of 200 to 130,000. Since each polymer having a carboxyl group or an acid anhydride group is contained in an appropriate amount, the initial adhesive strength, the adhesive strength after immersion in the electrolyte solution, and the change in the appearance of the molded part after immersion in the electrolyte solution are all balanced. It was well filled.

Among them, the adhesives of Examples 13 to 20 showed excellent performance in all the tests.
In the adhesives of Examples 13 to 20, the acid value P of the polyolefin resin (A) was in a preferable range of 0.02 to 1.2, so that the adhesives were immersed in a long-term electrolyte solution as compared with Examples 1 to 3 outside the preferable range. The later adhesive strength and the appearance of the molded part were excellent.
Further, in the adhesives of Examples 13 to 20, the polyolefin resin (A) is a binary copolymer of propylene and 1-butene, and the copolymerization ratio is propylene: 1-butene = 40: 60 to 80:20. Therefore, the initial adhesive strength was excellent as compared with Examples 4 to 7 outside the suitable range.
Further, in the adhesives of Examples 13 to 20, the polymer (B) having a carboxyl group or an acid anhydride group is the sum of the polyolefin resin (A) and the polymer (B) having a carboxyl group or an acid anhydride group 100. Since it was blended in a preferable range of 0.5 to 4% by weight with respect to% by weight, the adhesive strength after immersion in the electrolyte solution and the appearance of the molded portion were excellent as compared with Example 8 outside the suitable range.
Further, since the adhesives of Examples 13 to 20 had a Z / (P * i + X * j) in a preferable range of 0.5 to 7, the initial adhesive strength was higher than that of Examples 9 to 11 outside the preferable range. Both were excellent after immersion in the electrolyte solution.
Further, since the adhesives of Examples 13 to 20 use a curing agent having an isocyanate group or an epoxy group as a curing agent, they are immersed in an electrolyte solution as compared with Example 12 using a curing agent having an aziridine group. The later adhesive strength and the appearance of the molded part were excellent.
Further, in the adhesives of Examples 13 to 20, the polymer (B) having a carboxyl group or an acid anhydride group is a homopolymer (b-1) of an unsaturated carboxylic acid or an acid anhydride thereof, or a non-polymer. Since it is a polymer (b-2) of a saturated carboxylic acid or an acid anhydride thereof and at least one selected from the group consisting of an aromatic vinyl compound, an aliphatic α-olefin compound, and a conjugated diene compound, the above-mentioned simple substance is used. Compared with Example 21 in which the polymer (B) in which the polymer was not polymerized was blended, the adhesive strength after immersion in the electrolyte solution and the appearance of the molded portion were excellent.

The adhesive composition according to the present invention can be suitably used for packaging materials (laminates) for forming containers for power storage devices such as lithium ion batteries, electric double layer capacitors, and lithium ion capacitors.
In addition, the adhesive composition according to the present invention is a packaging material for forming a container for a power storage device, as well as various industrial fields such as construction, chemistry, medical treatment, automobiles, etc., which are required to have high adhesive strength and chemical resistance. Can be suitably used for forming a laminated body in.

Claims (12)

An adhesive composition containing a polyolefin resin component and a curing agent (C).
The polyolefin resin component
A polyolefin resin (A) having a carboxyl group or an acid anhydride group, having a melting point of 55 to 100 ° C. and a weight average molecular weight of 40,000 to 400,000, and
Contains a polymer (B) having a carboxyl group or an acid anhydride group and having a weight average molecular weight of 200 to 13000.
The content of the polymer (B) is 0.2 to 5.0% by weight with respect to 100% by weight of the sum of the polyolefin resin (A) and the polymer (B).
An adhesive composition, wherein the curing agent (C) has at least one functional group selected from the group consisting of an isocyanate group, an epoxy group, a carbodiimide group, and an aziridine group. The adhesive composition according to claim 1, wherein the acid value X (mmol / g) of the polymer (B) is 1.2 to 20. The adhesive composition according to claim 1 or 2, wherein the acid value P (mmol / g) of the polyolefin resin (A) is 0.02 to 1.2. When the polyolefin resin (A) is i (g), the polymer (B) is j (g), and the functional group of the curing agent is Z (mmol), Z / (P * i + X * j) is The adhesive composition according to any one of claims 1 to 3, wherein the adhesive composition is 0.3 to 10. The polymer (B)
A homopolymer of unsaturated carboxylic acid or its acid anhydride (b-1), or
A polymer (b-2) of an unsaturated carboxylic acid or an acid anhydride thereof and at least one selected from the group consisting of an aromatic vinyl compound, an aliphatic α-olefin compound, and a conjugated diene compound. The adhesive composition according to any one of 1 to 4, which is characteristic. The adhesive composition according to any one of claims 1 to 5, wherein the polyolefin resin (A) has a melting point of 65 ° C. to 90 ° C. and a weight average molecular weight of 100,000 to 300,000. It has an adhesive layer between the metal foil and the heat-sealed resin film layer,
A laminate, wherein the adhesive layer is formed from the adhesive composition according to any one of claims 1 to 6. A surface treatment layer is provided between the metal foil and the adhesive layer.
The laminate according to claim 7, wherein the surface treatment layer is formed from a treatment agent having a functional group that reacts with the functional group of the curing agent (C). The laminate according to claim 8, wherein the functional group that reacts with the functional group of the curing agent (C) in the treatment agent is at least one selected from the group consisting of a carboxyl group, a hydroxyl group, and an amino group. .. In order from the outside, in a packaging material for a power storage device that requires an outer layer side resin film, an outer layer side adhesive layer, a metal leaf, an inner layer side adhesive layer, and a heat-sealing resin film.
A packaging material for a power storage device, wherein the inner layer side adhesive layer is formed from the adhesive composition according to any one of claims 1 to 6. A container for a power storage device formed of the packaging material for a power storage device according to claim 10, wherein a heat-sealing resin film constitutes an inner surface. A power storage device using the storage device container according to claim 11.

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